To characterise the difference of a feature over time in 4 primary groups, non_neg / noo_pos / txp_neg / txp_pos, we use the mean statistic of the feature at a certain time.
Visualization comparison
Left: empirical
the error bar is 95% confidence interval of feature mean at given time, calculated from standard error (se), (note: larger the sample size n, smaller the se)
Right: linear regression
the ribbon is 95% confidence interval of estimated mean response